Jae-Sang Oh

Endovascular Treatment of Dural Arteriovenous Fistulas: Single Center Experience

Objective Treatment of intracranial dural arteriovenous fistulas (dAVFs) remains a challenge. However, after introduction of Onyx, transarterial approach is the preferred treatment option in many centers. We report our experience of dAVFs embolization with special emphasis on transarterial approach. Methods Seventeen embolization procedures were performed in 13 patients with dAVFs between Jan 2009 and Oct 2014. Clinical symptoms, location and type of fistulas, embolization methods, complications, radiological and clinical outcomes were evaluated using charts and PACS images. Results All 13 patients had symptomatic lesions. The locations of fistulas were transverse-sigmoid sinus in 6, middle fossa dura in 4, cavernous sinus in 2, and superior sagittal sinus in 1 patient. Cognard types were as follows : I in 4, IIa in 2, IIa+IIb in 5, and IV in 2. Embolization procedures were performed ≥2 times in 3 patients. Nine patients were treated with transarterial Onyx embolization alone. One of these required direct surgical puncture of middle meningeal artery. Complete obliteration of fistulas was achieved in 11/13 (85%) patients. There were no complications except for 1 case of Onyx migration in cavernous dAVF. Modified Rankin scale score at post-operative 3 months were 0 in 11, and 3 in 2 patients. Conclusion Transarterial Onyx embolization can be a first line therapeutic option in patients with dAVFs. However, transvenous approach should be tried first in cavernous sinus dAVF because of the risk of intracranial migration of liquid embolic materials. Furthermore, combined surgical endovascular approach can be considered as a useful option in inaccessible route.

Which One Is Better to Reduce the Infection Rate, Early or Late Cranioplasty?

Objective Decompressive craniectomy is an effective therapy to relieve high intracranial pressure after acute brain damage. However, the optimal timing for cranioplasty after decompression is still controversial. Many authors reported that early cranioplasty may contribute to improve the cerebral blood flow and brain metabolism. However, despite all the advantages, there always remains a concern that early cranioplasty may increase the chance of infection. The purpose of this retrospective study is to investigate whether the early cranioplasty increase the infection rate. We also evaluated the risk factors of infection following cranioplasty. Methods We retrospectively examined the results of 131 patients who underwent cranioplasty in our institution between January 2008 and June 2015. We divided them into early (≤90 days) and late (>90 days after craniectomy) groups. We examined the risk factors of infection after cranioplasty. We analyzed the infection rate between two groups. Results There were more male patients (62%) than female (38%). The mean age was 49 years. Infection occurred in 17 patients (13%) after cranioplasty. The infection rate of early cranioplasty was lower than that of late cranioplasty (7% vs. 20%; p=0.02). Early cranioplasty, non-metal allograft materials, re-operation before cranioplasty and younger age were the significant factors in the infection rate after cranioplasty (p<0.05). Especially allograft was a significant risk factor of infection (odds ratio, 12.4; 95% confidence interval, 3.24–47.33; p<0.01). Younger age was also a significant risk factor of infection after cranioplasty by multivariable analysis (odds ratio, 0.96; 95% confidence interval, 0.96–0.99; p=0.02). Conclusion Early cranioplasty did not increase the infection rate in this study. The use of non-metal allograft materials influenced a more important role in infection in cranioplasty. Actually, timing itself was not a significant risk factor in multivariate analysis. So the early cranioplasty may bring better outcomes in cognitive functions or wound without raising the infection rate.

Endovascular Treatment for Ruptured Distal Anterior Inferior Cerebellar Artery Aneurysm

A 42-year-old woman presented with Hunt and Hess grade (HHG) III subarachnoid hemorrhage (SAH) caused by a ruptured left distal anterior inferior cerebellar artery (AICA) aneurysm. Computed tomography showed a thin SAH on the cerebellopontine angle cistern, and small vermian intracerebral hemorrhage and intraventricular hemorrhage in the fourth ventricle. Digital subtraction angiography revealed the aneurysm on the postmeatal segment of left distal AICA, a branching point of rostrolateral and caudomedial branch of the left distal AICA. Despite thin caliber, tortuous running course and far distal location, the AICA aneurysm was obliterated successfully with endovascular coils without compromising AICA flow. However, the patient developed left side sensorineural hearing loss postoperatively, in spite of definite patency of distal AICA on the final angiogram. She was discharged home without neurologic sequela except hearing loss and tinnitus. Endovascular treatment of distal AICA aneurysm, beyond the meatal loop, is feasible while preserving the AICA flow. However, because the cochlear hair cell is vulnerable to ischemia, unilateral hearing loss can occur, possibly caused by the temporary occlusion of AICA flow by microcatheter during endovascular treatment.

Efficacy of Balloon-Guiding Catheter for Mechanical Thrombectomy in Patients with Anterior Circulation Ischemic Stroke

Objective To evaluate the efficacy of balloon guiding catheter (BGC) during thrombectomy in anterior circulation ischemic stroke. Methods Sixty-two patients with acute anterior circulation ischemic stroke were treated with thrombectomy using a Solitaire stent from 2011 to 2016. Patients were divided into the BGC group (n=24, 39%) and the non-BGC group (n=38, 61%). The number of retrievals, procedure time, thrombolysis in cerebral infarction (TICI) grade, presence of distal emboli, and clinical outcomes at 3 months were evaluated. Results Successful recanalization was more frequent in BGC than in non-BGC (83% vs. 66%, p=0.13). Distal emboli occurred less in BGC than in non-BGC (23.1% vs. 57.1%, p=0.02). Good clinical outcome was more frequent in BGC than in non-BGC (50% vs. 16%, p=0.03). The multivariate analysis showed that use of BGC was the only independent predictor of good clinical outcome (odds ratio, 5.19: 95% confidence interval, 1.07–25.11). More patients in BGC were successfully recanalized in internal carotid artery (ICA) occlusion with small retrieval numbers (<3) than those in non-BGC (70% vs. 24%, p=0.005). In successfully recanalized ICA occlusion, distal emboli did not occur in BGC, whereas nine patients had distal emboli in non-BGC (0% vs. 75%, p=0.001) and good clinical outcome was superior in BGC than in non-BGC (55.6% vs. 8.3%, p=0.01). Conclusion A BGC significantly reduces the number of retrievals and the occurrence of distal emboli, thereby resulting in better clinical outcomes in patients with anterior circulation ischemic stroke, particularly with ICA occlusion.

Cervical epidural abscess: rare complication of bacterial endocarditis with streptococcus viridans: a case report.

Although many patients with infective endocarditis (IE) complain of joint, muscle, and back pain, infections at these sights are rare. The incidence of spinal abscess in cervical spine complicating endocarditis is very rare. Although the surgical management is the mainstay of treatment, conservative treatment can get success in selected patients. We report a patient with cervical epidural abscess due to Streptococcus viridans endocarditis. Both epidural abscess and IE were managed conservatively with intravenous antibiotics for 8 weeks, with recovery. It is important to remind spinal epidural abscess can occur in those patients with bacterial endocarditis.

Ligamentum flavum cyst of lumbar spine: a case report and literature review.

Ligamentum flavum cysts have rarely been reported and known to be the uncommon cause of spinal compression and radiculopathy. A 63-year-old man presented right sciatica lasting for 1 month. Lumbar computerized tomography and magnetic resonance imaging demonstrated an extradural cystic mass adjacent to the L5-S1 facet joints. Partial hemilaminectomy and flavectomy at the L5-S1 space were performed, and then the cystic mass was excised. Histopathology confirmed a connective tissue cyst, which is consistent with the ligamentum flavum. Microscopic examination of the cyst wall revealed that it is closely packed collagen fibril. The symptom of patient was improved after surgery. Because of rarity of ligamentum flavum cysts and nonspecific clinical and radiologic findings, the preoperative diagnosis is not easy. The histologic features of ligamentum flavum cysts are distinct from other cystic lesion of lumbar spine. This study presents a case and literature review of ligamentum flavum cyst. We summarize the pathophysiology, occurrence, differential diagnosis of rare ligamentum flavum cyst, especially on lumbar spine.

A Morphometric Study of the Obturator Nerve around the Obturator Foramen

Objective Obturator neuropathy is a rare condition. Many neurosurgeons are unfamiliar with the obturator nerve anatomy. The purpose of this study was to define obturator nerve landmarks around the obturator foramen. Methods Fourteen cadavers were studied bilaterally to measure the distances from the nerve root to relevant anatomical landmarks near the obturator nerve, including the anterior superior iliac spine (ASIS), the pubic tubercle, the inguinal ligament, the femoral artery, and the adductor longus. Results The obturator nerve exits the obturator foramen and travels infero-medially between the adductors longus and brevis. The median distances from the obturator nerve exit zone (ONEZ) to the ASIS and pubic tubercle were 114 mm and 30 mm, respectively. The median horizontal and vertical distances between the pubic tubercle and the ONEZ were 17 mm and 27 mm, respectively. The shortest median distance from the ONEZ to the inguinal ligament was 19 mm. The median inguinal ligament lengths from the ASIS and the median pubic tubercle to the shortest point were 103 mm and 24 mm, respectively. The median obturator nerve lengths between the ONEZ and the adductor longus and femoral artery were 41 mm and 28 mm, respectively. Conclusion The obturator nerve exits the foramen 17 mm and 27 mm on the horizontal and sagittal planes, respectively, from the pubic tubercle below the pectineus muscle. The shallowest area is approximately one-fifth medially from the inguinal ligament. This study will help improve the accuracy of obturator nerve surgeries to better establish therapeutic plans and decrease complications.

Transcranial direct middle meningeal artery puncture for the onyx embolization of dural arteriovenous fistula involving the superior sagittal sinus.

A 66-year-old woman presented with intermittent paraparesis and generalized tonic-clonic seizure. Cerebral angiography demonstrated dural arteriovenous fistula (AVF) involving superior sagittal sinus (SSS), which was associated with SSS occlusion on the posterior one third. The dural AVF was fed by bilateral middle meningeal arteries (MMAs), superficial temporal arteries (STAs) and occipital arteries with marked retrograde cortical venous reflux. Transfemoral arterial Onyx embolization was performed through right MMA and STA, but it was not successful, which resulted in partial obliteration of dural AVF because of tortuous MMA preventing the microcatheter from reaching the fistula closely enough. Second procedure was performed through left MMA accessed by direct MMA puncture following small decortications of cranium overlying the MMA using diamond drill one week later. Microcatheter could be located far distally to the fistula through 5 F sheath placed into the MMA and complete obliteration of dural AVF was achieved using 3.9 cc of Onyx.

Influence of Gender on Occurrence of Chronic Subdural Hematoma; Is It an Effect of Cranial Asymmetry?

Objective Chronic subdural hematoma (CSDH) is a condition mostly present in older people. Men are more commonly affected than women. Several theories about male predominance could not enough to explain the reason for male predominance on CSDH. The purpose of this study is to find out whether there were any differences in the anatomy of cranium, which may contribute the pathogenesis or risk factors of CSDH. Methods The study population was consisted of 87 patients with CSDH and 100 patients with transient ischemic attack (TIA) from 2006 to 2013. We classified into four groups; group A (CSDH male 47), group B (CSDH female 40), group C (TIA male 50), and group D (TIA female 50). We measured the size of the cranium in the computed tomography scans, retrospectively. We define the difference of cranium (Dc), which is difference between the right and left radiuses. Results The Dc was significantly higher in patients with CSDH (group A and B)(p=0.03). The mean Dc was 3.49 mm in CSDH group (group A and B) and 2.14 mm in TIA group (group C and D). The mean Dc of CSDH group was significantly larger than that of TIA group (by t-test, p<0.01). Conclusion Size and asymmetry of the cranium may be a risk factor of CSDH. Gender differences in the anatomy of cranium may contribute pathogenesis of CSDH.

Clinical Features of Interhemispheric Subdural Hematomas

Objective Interhemispheric subdural hematoma (IHSDH) is uncommon, because of their unusual location. However, it is a distinct lesion with its unique characteristics. We investigated clinical features and outcomes of consecutive 42 patients with IHSDH, retrospectively. Methods From 2006 to 2015, we treated 105 patients with IHSDH. All patients were diagnosed by computed tomography (CT) or magnetic resonance imaging. We selected 42 patients with thick (3 mm or more) IHSDH. We retrospectively reviewed the clinical and radiological findings, management and outcomes. Results The male to female ratio was 2:1. Two thirds of the patients were over 60 years old. Slip or fall was the most common cause of trauma. The level of consciousness on admission was Glasgow Coma Scale (GCS) 13 to 15 in 25 patients. The most common symptom was headache. All IHSDH was hyperdense in CT at the time of diagnosis. IHSDH frequently accompanied convexity subdural hematoma. The outcome was favorable in 27 patients, however, six patients were expired. Twenty-two patients were managed conservatively. Surgery was performed in ten patients to remove the concurrent lesion. The outcome was poor in spontaneous one, patients with low GCS, and patients with conservative treatment. Conclusion IHSDH is rare especially the isolated one. The outcome was dependent to the severity of injury. Surgery may be helpful to remove the concurrent mass lesion, however, conservative treatment is generally preferred.